Each year, an estimated ten thousand fires occur in buildings that are seven stories or higher. Hundreds of firefighters and police risk their life every day by entering burning buildings to save trapped civilians. Additionally, terrorism, hostage situations, and violent crime rampages worldwide are increasing, often leaving people trapped high above the streets, waiting for rescue.
An estimated 2,726 people died on Sep. 11, 2001, at the World Trade Center in New York City. Of that number, 343 were firemen who entered the building to save lives. An estimated 200 people were trapped civilians who willingly jumped from the buildings before the buildings collapsed. Though 9/11 was an extreme situation, it is not uncommon for victims of high rise fires to jump as a last resort to escape smoke and fire. For many fire victims, exit routes are too slow or inaccessible due to extremely hot flames and smoke. For overweight or physically impaired individuals, stairs are not an option. Too frequently victims are trapped and forced to wait for rescue.
Over the years, many devices have been created attempting to address the problem of controlled descent in an emergency situation, either to prevent work-related falls or for emergency descent from buildings. Many of these prior art devices rely solely upon hydraulic or other fluid braking systems. Such devices have a relatively short life, depending on the nature of the fluid, and risk failure due to low or insufficient fluid levels. Because emergency situations rarely occur, and even more rarely occur more than once for a single building, emergency devices must be able to be stored for extended periods of time without maintenance without any risk of degradation of functionality.
Other prior art devices are manual in nature. U.S. Pat. No. 5,842,542, uses a manual braking system, such as a rope windlass system, to slow the passage of a rope as the person descends. However, wear on the rope caused by the friction of the manual braking system makes such a system dependent upon the abilities of the user, thus are less reliable for members of the population who do not have the capacity to exert sufficient force to slow the descent.
Yet other prior art devices include a complexity of mechanics to make them unwieldy and inherently less reliable. Such devices are found in U.S. Pat. No. 3,946,989, and U.S. Pat. No. 6,745,872. Not only are such complex mechanisms expensive to manufacture, the multiple parts makes them inherently unreliable. Similarly, prior art devices that include spring mechanisms, such as that found in U.S. Pat. No. 3,760,910, include an element that may not store over time, may break under certain heavier weights, or may not extend sufficiently under certain lighter weights.
Thus, there remains a need for a reliable device for enabling the controlled descent of persons of a range of ages, weights, and abilities from high buildings in emergency situations.